Decadal Survey 2020 APC White Papers Led by IPAC Scientists

Direct Imaging and Spectroscopy of Exoplanets with the James Webb Space Telescope
Beichman, C.; Barrado, D.; Belikov, R. and 38 more

Coronagraphic imaging and direct spectroscopy of young planets with JWST will add new insights into our understanding of the formation and evolution of exoplanets. This paper focuses on how JWST will add to our knowledge of young giant planets located at orbits beyond a few AU for the closest stars and a few 10s of AU for more distant ones.

Toward Finding Earth 2.0: Masses and Orbits of Small Planets with Extreme Radial Velocity Precision
Ciardi, D.; Bean, J.; Burt, J. and 12 more

Having discovered that Earth-sized planets are common, we are now embarking on a journey to determine if Earth-like planets are also common. To achieve this forward-looking goal, we must determine the masses and orbits of the planets; as such, the development of high quality precision radial velocity instruments and facilities is needed.

Mapping out the time-evolution of exoplanet processes
Christiansen, J.; Beichman, C.; Ciardi, D. and 4 more

In this white paper we identify predicted correlations, particularly trends in exoplanet populations, radii, orbits and atmospheres with host star age, that will allow us to begin identifying the dominant processes governing the formation and evolution of exoplanet systems.

Understanding Exoplanet Atmospheres with UV Observations I: NUV and Blue/Optical
Christiansen, J.; Barclay, T.; Fossati, L. and 9 more

In this white paper we focus on the science case for exoplanet observations at near-UV/blue optical wavelengths. Scattering information encoded in at these wavelengths can distinguish the cause of muted spectral features. These wavelengths also capture atmospheric escape processes, and help characterize mass loss from exoplanet atmospheres.

On the Origins of the Initial Mass Function
Paladini, R.; Povich, M.; Armus, L. and 13 more

In order to establish if the IMF and CMF are Universal, it is necessary to: 1) perform multi-wavelength large-scale imaging and spectroscopic surveys; 2) require an angular resolution of <0:1" in the optical/near-IR and <5" in the far-IR; 3) achieve far-IR sensitivities to probe 0.1 M cores at 2--3 kpc.

The Need for Infrared Astrometry of Brown Dwarfs in the Post-Gaia Era
Kirkpatrick, J.; Abdurrahman, F.; Best, W. and 12 more

Brown dwarf research in the next decade will be reliant on extending high- precision astrometry in wavelength and temporal coverage. Future astrometry will enable measures of the low-mass cutoff of star formation, allow for the discovery of cold brown dwarf analogs to cold (exo)planets, and enable mass measurements for single and binary systems .

Opportunities in Time-domain Stellar Astrophysics with the NASA Near-Earth Object Camera (NEOCam)
Kirkpatrick, J.; Metchev, S.; Hillenbrand, L. and 14 more

NEOCam will provide valuable data for the discovery and characterization of cold brown dwarfs, exoplanet analogs with weather variations, pre-main sequence variables, infrared-only transients, and more. For a relatively small investment, NASA can realize the full potential of NEOCam data by providing additional data products and transient alerting.

Illuminating the dark universe with a very high density galaxy redshift survey over a wide area
Wang, Y.; Bean, R.; Behroozi, P. and 30 more

A very high number density galaxy redshift survey over a wide area (HD GRS Wide) spanning the redshift range of 0.5<z<4 using the same tracer, carried out using massively parallel wide field multi-object slit spectroscopy from space, will provide definitive dark energy measurements with minimal observational systematics by design.

CASTOR: A Wide-Field, UV Space Telescope
Capak, P.; Balogh, M.; Christiansen, J. and 25 more

A description of the Canadian Lead CASTOR UV Space Telescope

ATLAS Probe: Breakthrough Science of Galaxy Evolution, Cosmology, Milky Way, and the Solar System
Wang, Y.; Dickinson, M.; Hillenbrand, L. and 48 more

ATLAS (Astrophysics Telescope for Large Area Spectroscopy) is a concept for a NASA probe-class space mission that will achieve groundbreaking science in all areas of astrophysics. It has a 1.5m aperture telescope, 0.4 sq deg FoV, R = 1000 slit spectroscopy over 1-4mm, and obtains 6,000 spectra simultaneously using digital micro-mirror devices.

Enhancing WFIRST Science with the Addition of a Redder Filter
Helou, G.; Stauffer, J.; Kirkpatrick, J. and 22 more

We outline a number of science advantages for adding a K or Ks filter (lambda_c 2.15 microns) and propose to extend the wavelength coverage for WFIRST into the K-band, where the gains of going to space are much more pronounced than at shorter wavelengths.

JSP: Joint Survey Processing of LSST/Euclid/WFIRST
Chary, R.; Brammer, G.; Capak, P. and 23 more

Joint survey processing (JSP) is the pixel level combination of LSST, Euclid, and WFIRST datasets. This white paper highlights the scientific motivation, computational and algorithmic needs to build joint pixel level processing capabilities, which the individual projects by themselves will not be able to support.

Supporting Archival Research with Euclid and SPHEREx Data
Teplitz, H.; Helou, G.; Rhodes, J. and 8 more

Robust funding for archival research through the NASA Astrophysics Data Analysis Program (ADAP) has been a successful and vital investment for NASA. In the mid-2020s, the largest projects for ADAP will be new missions, Euclid and SPHEREx. We provide an overview of potential archival research, and we estimate the needed increase in funding.

Cosmology in the 2020s Needs Precision and Accuracy: The Case for Euclid/LSST/WFIRST Joint Survey Processing
Chary, R.; Armus, L.; Faisst, A. and 10 more

Cosmological breakthroughs in the 2020s will arise from measuring the redshift evolution of dark energy, resolving the tension in the expansion rate of the Universe, and understanding the impact of dark matter on galaxy substructure. Joint processing of Euclid/LSST/WFIRST data provides the most compelling, economical and tractable path forward.

Making the Case for Visualization
Hurt, R.; Wyatt, R.; Subbarao, M. and 7 more

Visual representation of information is a fundamental tool for advancing our understanding of science. It enables the research community to extract new knowledge from complex datasets, and plays a vital role in communicating new results to the public. We establish the case for support of astronomy visualization and its community of practice.

Synergizing Deep Field Programs Across Multiple Surveys
Capak, P.; Scolnic, D.; Davidzon, I.

A critical component of many past, present and future astronomical surveys is a dedicated deep field program. We argue these should be explicitly coordinated and considered in project design to maximize the scientific output of these important observations.

Making the Case: Principles for Workforce, Education, Public Outreach and Communications (WEPOC)
Squires, G.; Brewer, J.; Roberts, T. and 4 more

A group of 20+ astronomy and high-energy physics leaders have been compiling a body of knowledge to "make the case" for the importance of WEPOC in large science projects, and how WEPOC should be developed and implemented. These include 8 principles and practices we recommend for inclusion in the Astro2020 report.

A Science Platform Network to Facilitate Astrophysics in the 2020s
Desai, V.; Allen, M.; Arviset, C. and 30 more

We advocate for the adequate funding of data centers to develop and operate "science platforms", which will provide storage and computing resources for the astronomical community to run analyses near the data. Furthermore, these platforms should be connected to enable cross-center analysis and processing.